The present invention relates generally to the field of medical catheters, and more specifically to a catheter used to deliver medical stents. In one aspect, the invention further relates to methods for deploying stents in vessels such that a side opening in the stent wall is aligned with an ostium of a branch vessel. In other aspects, the invention is related to the management of guidewires over which such catheters are introduced.
A stent is a type of endoprosthcsis device, typically intraluminally placed or implanted within a vein, artery, or other tubular body organ for treating an occlusion, stenosis, aneurysm, collapse, dissection, or weakened, diseased, or abnormally dilated vessel or vessel wall, by expanding the vessel or by reinforcing the vessel wall. In particular, stents are quite commonly implanted into the coronary, cardiac, pulmonary, neurovascular, peripheral vascular, renal, gastrointenstinal and reproductive systems, and have been successfully implanted in the urinary tract, the bile duct, the esophagus, the tracheo-bronchial tree and the brain, in order to reinforce these body organs. Two important currant widespread applications for stents are for improving angioplasty results by preventing elastic recoil and remodeling of the vessel wall and for treating dissections in blood vessel walls caused by balloon angioplasty of coronary arteries as well as peripheral arteries. Conventional stents have been used for treating more complex vascular problems, such as lesions at or near bifurcation points in the vascular system, where a secondary artery branches out of a larger, main artery, with limited success rates, as described by Chevalier, B., et al., in the American Journal of Cardiology, 82: 943-949, 1998; Yamashita, T., et al., in the Journal of American Coll ge of Cardiology, 35: 1145-1151, 2000; and Satler, S., et al., in Catheterization and Cardiovascular Interventions, 50: 411-412, 2000.
Conventional stent designs typically feature a straight tubular, single type cellular structure, configuration, or pattern which is repetitive through translation along the longitudinal axis, and sometimes also along the radial axis of the stent. The repeating structure, configuration, or pattern has strut and connecting members that can impede blood flow at bifurcations. Furthermore, the configuration of struts and connecting members may obstruct the use of post-operative devices to treat a branch vessel in the region of a vessel bifurcation. For example, a physician may be unable to insert a branch stent through the ostium of a branch vessel of a vessel bifurcation in cases where treatment of the main vessel is suboptimal as a result of displacing diseased tissue (plaque shifting or ‘snow plowing’), occlusion, vessel spasm, dissection with or without intimal flaps, thrombosis, embolism, and/or other vascular diseases. Accordingly, the use of regular stents to treat diseased vessels at or near a vessel bifurcation may create a risk of compromising the degree of patency of the main vessel, branch vessels, and/or the bifurcation point.
Non-conventional stents, such as a stent with a side opening for branch vessel access, or double stenting systems can be used to overcome some of the above limitations. Delivery of such non-conventional stents often requires the use of non-conventional catheters. For example, catheters with two lumens for guidewires—a main guidewire lumen and a branch guidewire lumen—are used to deliver stents with side branch access. Examples of such catheters are described, for example, in co-pending U.S. application Ser. No. 09/663,111, filed Sep. 15, 2000 and co-pending U.S. application Ser. No. 09/455,299, filed Dec. 6, 1999, both of which are incorporated herein by reference in their entireties.
However, the use of such non-conventional stents and catheters produces additional challenges, resulting from the use of more than one guidewire. After a guidewire is appropriately positioned within the patient body, a trailing end portion of the guidewire typically extends out of the patient body from the point of entry. It has been found that the trailing end portion of the guidewire outside the patient body can be rather difficult to manage and can interfer with the efficiency of the medical procedure performance. This is especially true when more than one guidewire is being used during a medical procedure. In such a case, the medical practitioner performing the procedure may confuse the trailing end portions of the guidewires protruding from the patient body with one another. Furthermore, long wires are difficult to manage and often require more than one individual for proper manipulation. This problem is exacerbated when more than one long wire is used.
When using multiple wires to introduce a catheter system, one condition that may occur is known as “wire crossing.” In such cases, the guidewires over which the catheter system is advanced intertwine within the guide catheter and vasculature. This condition may prevent the successful delivery of the catheter system by impeding its travel and subsequently, the alignment of the stent's side opening with the ostium of the branch vessel.
There is thus a widely recognized need for, and it would be highly advantageous to have, a dual guidewire catheter system that avoids the above limitations.